I am having the same issue as well. I got a 90000 error early this morning and have not been able to log in since then. I get an empty character screen, then it gives me a 2002 lobby error message. I contacted Square Enix, and they said it was an issue with my ISP or router, or blocked ports. I re-opened the ports the SE rep told me to, then nothing. I reset my router. Nothing.

SE rep said that they were receiving multiple reports of issues with people in Texas using Verizon FIOS. Both apply to me. I'm in the DFW area.